| Abstract: | Novel liquid crystalline copoly(ester imide)s were synthesized via polyesterification of triethyleneglycol bis(4-carboxyphenyl) ether ( 1e ), diacetoxybiphenyl, and diacids with imide moieties. The effects of composition on the changes of Tg, Tm, and Ti were examined by global TSC and DSC. Thermal gravimetric analyses (TGA) found that 4a–d and 5a–g possess higher thermal stability. Strong stir opalescence phenomenon and observations from polarized optical microscopy identified that 2b–e and 3a–d possess the typical schlieren texture of an enantiotropic nematic mesophase. The birefrigent melts of 4a–d and 5a–g, however, displayed particular liquid crystalline behavior. Copolymers with higher aromatic imide ring content ( 4a–d, 5a–g ) form a layered structure and an enantiotropic smectic mesophase in the melting state. The melt viscosity of the semetic mesophase was higher than the nematic mesophase which was observed by capillary rheometer. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1791–1803, 1998 |
